Pile driving apparatus

ABSTRACT

Pile driving apparatus adapted to apply a driving force to casing or piling to force same into the ground, wherein successive slugs of water are dropped under pressure to impart successive down blows to the apparatus, which blows are transmitted to the casing or piling, whereby increased blows can be imparted with a minimum weight for the apparatus.

4' 6 r u v Unite fittes tee i151 sesame Var-hell 1 Feb. 1 1 9'72 54] PILE DRIVING APPARATUS 2,664,269 12/1963 Knight et al. ..175 20 3,331,453 7/1967 Kermabon ..l75/6 [72] Inventor: Dexter L. Varuell, 4200 Scotland St., Apt.

Houston 77007 Primary ExaminerJames A. Leppink 22 il g 3 1970 Attorney-Havel, Wilson & Matthews [2!] Appl. No.: 60,289

[57] ABSTRACT [52] 11.8. C1 ..l73l90, 61/535, 173/ 126, Pile driving apparatus adapted to apply a driving force to cas- 175/6 ing or piling to force same into the ground, wherein successive [51 Int. Cl ..E02d 7/00 slugs of water are dropped under pressure to impart successive [58] Field of Search ..173/90, 126, 1; 175/6, 20; down blows to the apparatus, which blows are transmitted to 61/535 the casing or piling, whereby increased blows can be imparted v with a minimum weight for the apparatus. 56 R t C'ted 1 e 10 Claims, 12 Drawing Figures 7 H q STATES PATENTS 3,118,417 1/1964 Stanwick 11757? 2,176,477 ygrr ey et g l u 175/6 PATENIED FEB I 1972 SHEET 1 (IF 5 INVENTOR flexfer L. l/a//76 Hand & MaHLewA flTTORNE YS PATENTED FEB 1:972 3,638,738

flex/er Z. V0/v7e// INVENTOR mwef WJAW @Maflbem ATTORNEYS PILE DRIVING APPARATUS BACKGROUND OF THE INVENTION The field of this invention is pile driving apparatus. So far as is known, pile driving apparatus has heretofore operated on the principle of dropping a large steel mass or hammer. When attempting to use such prior apparatus for driving piles or cas ing in offshore waters, it has been impossible to develop sufficient downward force without using excessively massive apparatus. The heavy apparatus which has been required has limited offshore operations, and in some cases, has prevented their use because of the difficulties of handling and using such massive apparatus at offshore locations.

SUMMARY OF THE INVENTION The present invention relates to pile driving apparatus wherein far greater downward force can be applied to drive casing or piling downwardly into the ground than was possible with prior art apparatus, and wherein the apparatus may thus be made of lighter weight for producing a desired amount of pile driving force. The apparatus drops a slug of water or other liquid within the apparatus after confining a predetermined quantity of the water at an elevated location in the apparatus, with air or other gas under compression acting on the water or other liquid to increase the amount of impact force developed when the slug of water is dropped. The liquid which is dropped is subsequently pumped back to the elevated location so that successive downward blows are effected in controlled sequence.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation of the apparatus of this invention in position on the top of a casing or pile which is to be driven into the ground;

FIGS. 2A, 2B and 2C are vertical sectional views, partly in elevation, showing the lower, intermediate and upper portions, respectively, of the apparatus of FIG. I in detail;

FIG. 3 is a cross-sectional view taken on line 3-3 of FIG. 2A;

FIG. 4 is a cross-sectional view taken on line 4-4 of FIG. 2A;

FIG. 5 is a view taken on line 55 of FIG. 2A;

FIG. 6 is a cross-sectional view taken on line 6-6 of FIG.

FIG. 7 is a cross-sectional view taken on line 77 of FIG. 2C;

FIG. 8 is a partial cross-sectional view taken on line 8-8 of FIG. 28;

FIG. 9 is a detailed view of a portion of the gate operating mechanism illustrated in FIGS. 28 and 8; and

FIG. 10 is a schematic electrical diagram of one form of electrical control system for the apparatus of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawings, the letter C designates the casing or pile body of water. Although the pile C may be tubular in the form of easing or it may be solid and may be formed of different materials, the tenn pile" is used hereinafter to refer to any type of object which is to be driven into the ground or soil at any location. The apparatus of this invention includes generally a reservoir means R for receiving successive quantities of liquid in conjunction with a gas pressure means. Each predetermined quantity of liquid which is received in the reservoir means R is confined therein by a gate means G until the gate means G is released to drop the liquid as a slug downwardly into an impact section means S so that the slug of liquid hits the lower end of the impact section S to impart a downward blow or force to the entire apparatus which is in turn imparted to the pile C upon which the apparatus is disposed. Preferably, the apparatus of this invention includes a pump means P which recirculates water or other liquid within the apparatus after it has been dropped so that the liquid is returned to the reservoir means for repeating the procedure so as to obtain successive downward jars or blows with the apparatus on the upper end of the pile C to drive same downwardly into the ground in which the pile C is disposed.

Considering the invention more in detail, the reservoir means R has a gas or air chamber 12 which is preferably cylindrical in shape and which is formed by an outer cylinder 14, and an inner cylinder 16. The inner cylinder 16 fonns the outer wall for a liquid cylindrical chamber 17, the inner wall of which is formed by a cylindrical tube 18 having a bottom 18a therewith so as to form a pocket within the liquid chamber 17 which forms a part of the gas chamber 12. The upper end of the gas chamber 12 is closed by a cover 15 or any other suitable means. A lifting lug 15a is preferably mounted on the upper end of the plate 15 together with suitable internal gussets 15b or similar strengthening means, whereby the entire apparatus may be lifted and supported from the lifting lug orring 15a. A plurality of circularly disposed air pressure retaining valves 19 are mounted at the upper end of the liquid chamber 17 so as to control the communication between the gas chamber 12 and the liquid chamber 17. Each of the valves 19 is adapted to seat in a valve seat or opening 17a provided in the upper end of the liquid chamber 17, and each of such valves 19 is operated by any suitable means such aS doubleacting air pistons 19a which are disposed in cylinders 1%. Air for operating the pistons 19a to control the position of the valves 19 is supplied from any suitable source of air pressure such as an air pressure tank 20 (FIG. 213) through tubes 19c (FIG. 2C) which lead to four-way solenoid valves I9d which have suitable air or gas lines 192 and 19f to the opposite sides of the piston 19a for controlling the movements thereof. As will be more evident hereinafter, the valves 19 are normally in an opened position so that the openings 17a are open for maintaining communication from the gas reservoir 12 to the upper end of the liquid chamber 17 so that the gas within the chamber 12 is acted upon by the liquid as it rises in the liquid chamber 17. Prior to the liquid entering the chamber 17, the valves 19 are closed so that the gas pressure within the chamber 12 does not escape. Air or gas pressure is maintained at a desired level within the chamber 12 by any suitable means such as an air regulator 12a (FIG. 2B) which connects by means of a hose 12b to a source of air or gas pressure, such as the gas or air pressure tank 20. The pressure provided by such air or gas in the tank 20 may vary, but preferably it is about 250 pounds per square inch. The air or gas pressure within the chamber 12 is initially provided at a fixed amount such as about -90 pounds per square inch, and even though the water or liquid rises in the liquid chamber 17, compressing the gas above the liquid and within the chamber 12 to some extent, the pressure in the chamber 12 is not substantially changed due to the far greater volume of the air in the chamber 12 compared to the volume of the liquid in the chamber 17. When the water or liquid reaches its maximum level indicated at 171) (FIG. 2C), a tank level float switch 21 of any suitable construction is actuated for the purpose of opening the gate means G to release or drop the predetermined quantity of water or other liquid from the reservoir means R into the impact section S, as will be more evident hereinafter.

The liquid is received in the chamber 17 of the reservoir means R from a central pipe 22 which extends down to the pump means P, as will be more fully explained.

During the filling of the chamber 17 with the liquid from the pipe 22, the gate means G is in a closed position so as to confine the liquid thereabove in an annular space 23 which is externally of the pipe 22 and which is inwardly of a cylindrical sleeve 24 which forms the lower part of the reservoir means R. The details of the gate means G are illustrated in FIGS. 8 and 9 and an outer housing 25 is formed by a plurality of housing sections 25a which are welded or are otherwise formed together to form a substantially cylindrical housing 25 which is welded or is otherwise secured to the lower end of the cylindrical sleeve 24. The lower end of the housing 25 is connected to an external tube 26 (FIG. 28) by welding or other suitable means, which tube 26 forms a part of the impact section means S, as will be more fully explained.

The gate means G includes a plurality of gate members 27, one for each of the housing sections a, and with such members 27 functioning in pairs, as will be explained. The alternate pairs of the gate members 27 are at different elevations as can be seen in FIG. 9 so that a rotary actuator 30 may be utilized for actuating two of the gate members 27 which are disposed at different elevations. Thus, as viewed in FIG. 9, the central pair of gate members 27 are each mounted on a lower separate rotatable shaft 31 (FIG. 9). The gate members 27 which are immediately to the right and to the left of the two lower gate members 27 in FIG. 9 are each mounted on a separate upper rotatable shaft 32 (FIG. 8). Each shaft 32 is disposed directly above one of the shafts 31 and both are operated by the same rotary actuator 30 in a preferred form of the invention. Thus, each rotary actuator 30 preferably includes an outer cylinder 30a and a pair of internal pistons 30b and 30c which have suitable O-rings or seals therewith for maintaining a fluid seal as they move within the cylinder 30a. The piston 30b has a gear rack 30d therewith, while the piston 300 has a similar gear rack 30c therewith. The gear racks 30d and 30e mesh with a gear 33 which is mounted on a shaft 33a which extends outwardly from the cylinder 30a and which has thereon another gear 33b (FIG. 2B and FIG. 9). The gear 33b meshes with a gear 31a mounted on the shaft 31, and an idler gear 34 mounted on a shaft 34a extending from the housing 25 (FIG. 2B). The gear 34 serves as a reversing gear since it meshes with a gear 32a mounted on the shaft 32. Thus, as the pistons 30b and 300 are moved from the position shown in FIG. 9 towards each other, the gear 33 is rotated together with a shaft 33a, which imparts rotation to the other gears 33b, 31a, 34 and 32a. The pistons 30b and 30c are moved by the introduction of air or hydraulic fluid through inlet pipes or tubes 30f at the upper and the lower ends of the cylinder 300, or any other suitable means.

The gate members 27 are loosely pivotable on their respective shafts or rods 31 and 32. Thus, the gate member 27 which is to the left of the center in FIG. 9 is shown in FIG. 8 as having sleeves 27a, 27b, and 27: disposed around the shaft 32 so that the gate member 27 is thus mounted for rotation or turning movement relative to the shaft 32. The same rotatable or pivotal mounting of the gate members 27 which are disposed opposite the pins 31 in FIG. 9 is utilized for the mounting of such central gate members 27 shown in FIG. 9. Thus, the rotation of the shafts 31 and 32 impart no direct movement to the gate members 27. However, the gate members 27 are lifted from a substantially vertical position upwardly to a substantially horizontal'position by means of lifting lugs 35 which are secured to the shafts or rods 31 and 32. For purposes of illustration, FIG. 9 shows the lifting lugs 35 for the two central gate members 27 in the down position and the lifting lugs 35 for the upper gate members 27 in the up position, although they would normally be both in the same positions at the same time. In other words, the lifting lugs 35 for all of the gate members 27 on both sets of shafts 31 and 32 would all either be down as shown in FIG. 9 for the central gate members 27 or they would be up as shown for the right and left gate members 27 in FIG. 9. The lifting lugs 35 are preferably two in number for each gate member 27 and they are welded or otherwise secured to each of the shafts 31 and 32 by rings 35a such as illustrated in FIG. 8. It will he understood that the rings 35a which are visible in FIG. 8 are for the lifting lugs 35 for the upper gate members 27 shown in FIG. 9 and the corresponding rings for the lower lifting lugs 35 for the lower gate members 27 in FIG. 9 are hidden in FIG. 8.

Each of the gate members 27 has a latch lug 27d which is secured to each plate member 27 or is integral therewith and which terminates in a latch ring 27c. Adjacent latch rings 27c are positioned offset from each other (FIG. 8) and they have openings therein for receiving a latch pin or rod 37 which is actuated by a gate latch mechanism 40.

The gate latch mechanism 40 includes a spring-loaded piston 400 which is in a cylinder 4012 with a spring 400 which is acting to move the rod or latch pin 37 towards the pipe 22. Fluid is introduced inwardly of the piston 40e through a threeway solenoid valve 40b so as to withdraw the latch pin 37 when it is desired to let the gate members 27 swing downwardly from the closed position shown in FIGS. 8 and 9 to the substantially vertical open position. A gate latch return switch and control relay 40e is provided with the gate latch mechanism for automatic control in connection with the electrical control system, as will be more fully explained hereinafter.

A plurality of air entering valves 42 (FIG. 2B) are mounted below the gate means G to allow air to enter the annular space between the pipe 22 and the outer cylinder 26 of the impact section means S, except during the time that water or other liquid is being dropped as a slug when the gate mechanism G is opened, as will be more fully explained. At other times, the air enters the impact section S through the opened valves 42 as shown in FIG. 2B. The valves 42 are adapted to be closed by seating on the valve seats 42a which are preferably formed in each of the housing sections 25a. A cylinder 42b with a piston 42c therein is mounted with each of the valves 42 for operating same to retract the valves 42 to the closed position and for moving the valves 42 to the opened position. The piston 42c is thus a double-acting air piston which is supplied with air through a four-way solenoid valve 42d which has connection through a fluid line 42a with the air pressure tank 20 or any other suitable source of air pressure for operating the piston 420. The control for the solenoid valve 420' will be more evident in connection with the description of the electrical control system of FIG. 10 hereinafter.

The lower end of the outer housing 26 of the impact section S terminates in an open lower end within a chamber 47 which is at the lower end of the impact section S. The chamber 47 is formed inwardly of a valve housing 48 which is cylindrical and which is of a greater diameter than the outer cylinder 26 (FIG. 2A) and which has a valve means 50 formed at the lower end of the impact section S. The upper end of the chamber 47, outwardly of the cylinder 26, is covered by a cover plate 5! in which are mounted a plurality of air exhaust valves 52, the construction of which will be hereinafter explained.

Within the valve housing 48, a plurality of openings 48a which form valve seats are provided (FIGS. 2A and 4). A plurality of valve members 53 which are interconnected or are formed integrally with each other by a common connecting assembly 53a (FIG. 4), are disposed so that each of the valves 53 is adapted to seat within one of the valve seats 48a to close same to thereby close the lower end of the impact section S. The opening and closing of the valves 53 is controlled by a double-acting piston 55 for each of the valves 53, each of such pistons 55 being disposed within cylinders 56. Air or other fluid for operating the pistons 55 is introduced through a fourway solenoid valve 56a with each of the cylinders 56 (FIGS. 2A and 3).

Radial bracing plates 57 are preferably provided between the central pipe 22 and the valve housing 48 (FIG. 3) to thereby provided strengthening and suitable bracing for connection to additional braces 58 welded or otherwise affixed to each of the cylinders 56. It will be appreciated that any other suitable ribs or bracing may be incorporated in the structure to provide strength as needed for the apparatus. A plurality of air vents 48b are provided below the valve seats 48a so as to prevent a fluid lock within the system.

Also, for preventing a fluid lock within the impact section S during the movement of the slug of water downwardly therein for each impact below, the air exhaust valves 52 are provided. Each air exhaust valve 52 is preferably constructed as illustrated in FIGS. 2A and 5, wherein a valve element 52a in the form of a ball is formed at the lower end of each valve, with a stern 52b extending thereabove through a guide sleeve 52c. The stem 52b terminates in a disk or head 52d, and preferably a spring 60 is disposed between the head 52d and the guide sleeve 52c to resiliently support the valve element or ball 52a. The closure plate 51 has a valve seat or opening 510 therethrough for receiving each of the air exhaust valves 52. The weight of each valve element 52a normally holds each valve 52 in the open position as shown in FIG. 2A, but when each slug of water or other liquid reaches the chamber 47, and contacts the closed valves 53, the liquid will be diverted in an upward direction to force the valve elements 52a upwardly to thereby close the valve openings 51a. One of the disks or caps 52d on one of the valves 52 is adapted to contact an air exhaust valve switch 61 (FIG. 2A) to actuate same in connection with the electrical control system, as will be explained in connection with FIG. so that when the valves 52 have been moved to the closed position, the controls operate to effectuate an opening of the valves 53 to permit the water or other liquid then in the impact section S to pass through the openings 48a to the area below such openings 48a. Such release of the liquid from the impact sections S occurs after the full impact thereof has been imparted to the apparatus in a downward direction for obtaining the downward blow or force which is transmitted to the piling C. Ribs 53 and 54 are preferably welded on the plates 51 to each of the guide sleeves 52c (FIG. 2A and 5) to strengthen the support thereof. Also, strengthening ribs 55 are preferably welded internally of the outer housing 26 so as to extend from such housing 26 to the inner central pipe 22 as seen in FIG. 5. It will be appreciated that other strengthening ribs and braces may also be employed as desired or as necessary, and that such illustration of strengthening members is merely illustrative.

The pump means P includes a pump housing 65 which is secured to the lower end of the valve housing 48 by any suitable releasable means such as pivoted bolts 66 which are pivoted to the lower end of the housing 48 and which fit below flanges 66a on the upper end of the pump housing 65a.

The pump means P also includes a pump 70 which is preferably capable of delivering sufficient quantity of liquid to insure a rapid repetition rate of the slugs of liquid hitting in the impact section S. Preferably, the pump 70 is driven by electric motors 71 disposed on each side thereof. The pump 70 and the motor 71 are of known constructions and therefore the details are not illustrated in the drawings. In the preferred form of the invention, a nonrotatable conduit or pipe 71a extends through an opening 65b in the pump housing 65 for each of the motors 71, and an annular flexible seal 72 formed of rubber or other similar material engages the external surface of such conduits 71a (FIG. 2A).

The pump 70 is mounted on springs 73 which rests upon a base formed by a plurality of spaced vertically mounted plates 74 which are welded or otherwise secured to the housing 65 and also a pile cap 75 therebelow. The upper end of the pump 70 is connected to the lower end of the central flow pipe 22 by means of a flexible tubular connection 76 which is preferably a plurality of automobile tires which are bolted or otherwise affixed together to provide for elongation and compression longitudinally while still maintaining a watertight seal. A similar flexible connection 77 is provided below the pump 70 and is also preferably formed of automobile tires which are bolted or otherwise secured together. The lower end of the flexible connection 77 includes an inlet pipe 78 which is disposed above the pile cap 75 so that the water or other fluid may enter the pipe 78 and flow upwardly through the pump 70 and then through the pipe 22 to the reservoir R, as previously noted. Although the pile cap 75 may be formed in any desired shape, it preferably has a series of annular rings '74 a of different diameters for fitting into the bore of the casing or piling C which is engaged by the pile cap 75. A skirt 75b is also preferably disposed below the pile cap 75 and is welded thereto so as to be disposed externally of the piling C (FIG. 1

Although the operation of the apparatus of this invention may be controlled by various control systems, the preferred control system is illustrated schematically in FIG. 10. Thus, electrical terminals 80a and 80b are connected to a suitable source of electrical power, and a fuse 81 is disposed in the system with a master power switch 82. When the power switch 82 is closed, relays 83 and 84 are energized which closes the switches 83a and 84a. The closing of the switch 83a completes the electrical circuit to the pump 70 and turns it on so that the pump 70 then begins to pump water or other liquid from the interior of the pump housing 65 through the pump 70 and upwardly through the central pipe 22.

The closing of the switch 84a by the energizing of the control relay 84 actuates l2 solenoids 19d in corresponding solenoid actuated pilot valves which supply air to the double-acting pistons 19a to open the l2 air pressure retaining valves 19. It will be understood that the number of valves may be varied, and the number illustrated and described is by way of example only. It will also be understood that the pressure of the air or gas within the chamber 12 has previously been obtained by admission through the air inlet lines 12b and regulator 12a so that when the valves 19 are thus opened, air from the chamber 12 may then communicate with the chamber 17. However, since the water or other liquid is then being pumped upwardly to the pipe 22, the water forms a closure at the lower end of the chamber 17 to prevent an escape of the pressure as the water or other liquid rises within the chamber 17.

The water rises above the gate means G in the chamber 17 as it is pumped upwardly by the pump 70 until the water or other liquid level reaches the tank level float switch 21. When the switch 21 is closed, six control relays d (only one of which is illustrated) is energized so as to actuate the six threeway solenoid pilot valves 40d (FIGS. 8 and 10). The pilot valves 40d supply air to the six single-acting air pistons 40a (FIGS. 8 and 10) which are moved outwardly away from the central pipe 22 so as to pull the release gate latches 37 outwardly out of the latch rings 27.2 for each pair of the gate members 27. At that point, the lifting lugs 35 are in their lowered substantially vertical position shown for the central pair of lifting lugs 35 in FIG. 9 so that there is no support for the gate members 27 after the latch pins 37 have been pulled from the latch rings 27c, whereby such gate members 27 fall by gravity from the closed position downwardly to a substantially vertical open position. When the gate members 27 thus fall to the open position, a slug of water or other liquid which is above such gate members 27 is forced downwardly by gravity and by the gas pressure within the reservoir or chamber 12 acting on such liquid.

A stem 40f is disposed with each of the pistons 40a for actuating a gate latch return switch 40c which is schematically illustrated in FIG. 8 and also in FIG. 10 which deenergizes the control relays 140:! so that the springs return the latch pins 37 inwardly to the latching position.

In the meantime, the closing of the tank level float switch 21 also energizes and locks in its own contacts one control relay 153 which actuates six four-way solenoid pilot valves 153a which supply air for actuating six double-acting air pistons 55 to close the six water exhaust valves 53 therewith. The solenoid for the pilot valve 153a is shown in FIG. 10 with the same designation, and it is to be understood that throughout the diagram of FIG. 10, only one of the electrical components is illustrated but the enclosure indicates that there is a greater number of such electrical components and these correspond with the number of the actual units which they are operating as revealed by the other drawings.

The closing of the relay contact 153 also actuates solenoids 142d for the pilot valves 42d which supply air for actuating the 12 double-acting air pistons 42c to close the 12 air entering valves 42 so that as the water falls in the impact section S, it is not discharged through such air entering openings 42a.

The slug of water or other liquid is thus dropped through the open gate means G with the air entering valves 42 closed and with the valve members 53 closed so that when the slug of liquid hits such valve members 53 at the lower end of the impact section S, the downward force of such liquid is transmitted to the entire apparatus and thus to the pile C therebelow.

As the rapidly moving slug of liquid hits the lower end of the impact section means S, it acts upon the six air exhaust valves 52 to cause them to move to the closed position and to actuate the spring-loaded exhaust valve switch 61. Such switch momentarily closes upon contact so as to deenergize the control relay 153 which opens the water exhaust valves 53 and also opens the air entering valves 42. When the valves 53 open, the water or other liquid thereabove can flow to the pump housing 65 for subsequently being pumped again to the reservoir means R. The valves 53 remain open until closed by the actuation of the float switch 21, as explained above, so that any fluid leaking through the gate G while filling the chamber 17 will be permitted to pass below the valves 53.

The closing of the switch 61 also energizes and locks in its own contact six control relays 130 which actuate six four-way solenoid pilot valves 30g (FIG. 9). The pilot valves 30g supply air to the rotary actuators 30 so as to operate the pistons 30b and 300 to move them towards each other which causes the lift lugs 35 to move from the substantially vertical position to the substantially horizontal position. The lift lugs 35 carry the gate members 27 from the opened position to the closed position with them so that when the gate members 27 reach the closed position (FIG. 9), the spring-loaded latch pins 37 enter the latch rings 27e to lock the gate members 27 in the closed position. After completing its movement, each rotary actuator closes a rotary actuator return switch 30!: (FIG. 2B and FIG. which deenergizes the six control relays 130 to cause the lifting lugs to separate from the gates 27 and to be rotated back to the substantially vertical position shown for the central lifting lugs 35 in FIG. 9. This leaves the gate members 27 supported only by the latch pins 37. It should be noted that the latch pins 37 preferably have a tapered or inclined inner end 37a (FIG. 8) and the latch pins 37 are spring loaded by the springs 49c so that when the latch rings 272 are raised upwardly by the lifting of the gate members 27 with the lift lugs 35, the latch pins 37 are engaged on the tapered surface 37a by the latch pins 27e to retract sufficiently to permit the latch rings 27e to become aligned with each other and with the latch pin 37 which is disposed in position for latching same. Alternatively, the return of the latch pin 37 through the engagement of the stem 40f with the switch 40e may be delayed until the latch rings 27e are in alignment in the closed position.

During the time that the gate means G is being returned to the closed position, the pump 70 is continuously pumping water or other liquid upwardly through the central pipe 22 and is therefore filling the chamber 17 for the next slug of water which is to be delivered for the impact blow. it should be noted that the level of the liquid above the gate means G never falls below the level indicated at 170 (FIG. 28) when the slug of water is dropped by the opening of the gate mechanism G. This assures that leakage of the air or gas from the chamber 12 does not occur, even though the gate members 27 do not actually provide an airtight seal themselves even when in the closed position.

The cycle described above is repeated, except of course the power switch 82 remains closed and the relay switches 83a and 84a remain closed at all times until such power switch 82 has been opened. Therefore, so long as the switch 82 is closed, the valves 19 remain open. Successive slugs of water or other liquid may thus be delivered in predetermined quantities, and the sequence of such delivery is automatically controlled by any suitable control means such as that described in connection with FIG. 10.

Basically, it can thus be seen that the operation of the present invention involves the pumping or delivery of water or other liquid to the reservoir means R where such liquid is placed under pressure by means of the gas within the gas chamber 12. During the filling of the reservoir means R with the predetermined quantity of liquid. the gate means G is closed. and also the valves 53 are open. The air entering valves 42 are open.

After the predetermined quantity of the liquid has collected in the chamber 17, the gate means G is opened so that the slug of water drops or is forced downwardly by the gas pressure thereabove until it reaches the lower end of the impact section 5 which is formed by the closed valves 53, where it delivers the impact blow which is transmitted then through the apparatus to the piling C. Almost instantaneously upon receiving such blow, the valves 53 are opened, so that the water or other liquid then flows through the valves 53 to the pump area therebelow for recirculation back upwardly for another blow. Of course, there is a sufficient quantity of the liquid available so that there is a continuous circulation of the liquid from the pump upwardly to the reservoir means R to develop successive rapid blows with the apparatus. Tremendous power is developed by reason of the compressed gas acting on each slug of the liquid discharged downwardly into the impact section S.

It should be noted that the potential energy developed by the apparatus of this invention equals the work done in compressing the gas in the chamber 12 by the liquid as it rises in the chamber 17 plus the weight of each slug of the liquid multiplied by the distance each slug of liquid falls or is moved before hitting the lower end of the impact section S. The gas pressure in the chamber 12 pushes against the weight of the apparatus to force the liquid downwardly when the gate means G is opened. Therefore, it will be appreciated by those skilled in the an that the gas pressure in the chamber 12 must exert less downward force on the liquid in the chamber 17 than the weight of the apparatus itself, or otherwise, the apparatus would lift off the pile C rather than exerting a downward blow thereto. 7

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape, and materials as well as in the details of the illustrated construction may be made without departing from the spirit of the invention.

I claim: 1. Pile driving apparatus for driving pile into the ground, comprising:

an elevated liquid reservoir means for receiving and holding a predetermined quantity of liquid;

gate means forming a part of said reservoir means for holding liquid in said reservoir means when in a closed position and adapted to be moved to an open position to drop at least a portion of said predetermined quantity of liquid as a slug; and

an impact section means for permitting said slug of liquid to drop therethrough for a predetermined distance and hit the lower end thereof for imparting a blow to the apparatus and thereby to the pile upon which the apparatus is disposed.

2. The structure set forth in claim 1, including:

gas pressure means with said reservoir means for developing gas pressure in excess of atmospheric pressure above said predetermined quantity of liquid for increasing the downward movement of said slug of water when said gate means is opened to thereby develop an increased impact force on the apparatus when said slug hits the lower end of said impact section means.

3. The structure set forth in claim 1, including:

valve means at said lower end of said impact section means which is adapted to be opened after each said slug hits said lower end of said impact section means for discharging the liquid from said impact section means.

4. The structure set forth in claim 3, including:

pump means disposed below said valve means for receiving liquid from said impact section means when said valve means is opened and for continuously pumping liquid upwardly to said reservoir means for providing the liquid for successive slugs thereof which are dropped successively into said impact section means.

5. The structure set forth in claim 4, including:

gas pressure means with said reservoir means for developing gas pressure above said predetermined quantity of liquid for increasing the downward movement of each said slug of water when said gate means is opened to thereby develop an increased impact force on the apparatus when each said slug hits the lower end of said impact section means.

6. The structure set forth in claim 1, including:

pump means for pumping liquid to said reservoir means for providing liquid for successive slugs thereof.

7. The structure set forth in claim 1, including:

valve means at said lower end of said impact section means which is adapted to be opened after each said slug hits said lower end of said impact section means for discharging the liquid from said impact section means; and

control means operable by each slug of liquid for opening said valve means a short time after each said slug hits the lower end of said impact section.

8. The structure set forth in claim 1, including:

means for opening said gate means after each filling of said reservoir means with said predetermined quantity of liquid.

9. The structure set forth in claim 8, including means for closing said gate means after each slug of liquid has dropped into said impact section means therebelow.

10. The structure set forth in claim 1, wherein said gate means includes:

a plurality of pairs of gate members mounted for rotation between a closed position and an open position;

lugs adapted to lift said gate members from the open position to the closed position;

latch means for latching each of said pairs of gate members in the closed position; and

means for lowering said lifting lugs independently of said gate members after raising same with said gate members and latching same in the closed position with said latch means. 

1. Pile driving apparatus for driving pile into the ground, comprising: an elevated liquid reservoir means for receiving and holding a predetermined quantity of liquid; gate means forming a part of said reservoir means for holding liquid in said reservoir means when in a closed position and adapted to be moved to an open position to drop at least a portion of said predetermined quantity of liquid as a slug; and an impact section means for permitting said slug of liquid to drop therethrough for a predetermined distance and hit the lower end thereof for imparting a blow to the apparatus and thereby to the pile upon which the apparatus is disposed.
 2. The structure set forth in claim 1, including: gas pressure means with said reservoir means for developing gas pressure in excess of atmospheric pressure above said predetermined quantity of liquid for increasing the downward movement of said slug of water when said gate means is opened to thereby develop an increased impact force on the apparatus when said slug hits the lower end of said impact section means.
 3. The structure set forth in claim 1, including: valve means at said lower end of said impact section means which is adapted to be opened after each said slug hits said lower end of said impact section means for discharging the liquid from said impact section means.
 4. The structure set forth in claim 3, including: pump means disposed below said valve means for receiving liquid from said impact section means when said valve means is opened and for continuously pumping liquid upwardly to said reservoir means for providing the liquid for successive slugs thereof which are dropped successively into said impact section means.
 5. The structure set forth in claim 4, including: gas pressure means with said reservoir means for developing gas pressure above said predetermined quantity of liquid for increasing the downward movement of each said slug of water when said gate means is opened to thereby develop an increased impact force on the apparatus when each said slug hits the lower end of said impact section means.
 6. The structure set forth in claim 1, including: pump means for pumping liquid to said reservoir means for providing liquid for successive slugs thereof.
 7. The structure set forth in claim 1, including: valve means at said lower end of said impact section means which is adapted to be opened after each said slug hits said lower end of said impact section means for discharging the liquid from Said impact section means; and control means operable by each slug of liquid for opening said valve means a short time after each said slug hits the lower end of said impact section.
 8. The structure set forth in claim 1, including: means for opening said gate means after each filling of said reservoir means with said predetermined quantity of liquid.
 9. The structure set forth in claim 8, including means for closing said gate means after each slug of liquid has dropped into said impact section means therebelow.
 10. The structure set forth in claim 1, wherein said gate means includes: a plurality of pairs of gate members mounted for rotation between a closed position and an open position; lugs adapted to lift said gate members from the open position to the closed position; latch means for latching each of said pairs of gate members in the closed position; and means for lowering said lifting lugs independently of said gate members after raising same with said gate members and latching same in the closed position with said latch means. 